Manufacture of artificial silk



Jan. 24,1939.

P. ESSELMAN N MANUFACTURE OF ARTIFICIAL SILK Filed J uly 25, 1954 i llunl Patented Jan. 24, 1939 UNITED. STATES PATENT OFFICE many, assignorto I.

G. Farbenindustrie Aktiengesellschaft, Frankfort-on-the-Main, GermanyApplication July 25, 1934, Serial No. 736,946 In Germany July 28, 1933 4Claims.

My present invention relates to the manufacture of artificial silk andmore particularly to an improvement in the manufacture of artificialsilk according to the bobbin spinning system.

One of its objects is an improvement in the manufacture of artificialsilk according to the bobbin spinning system which is efficient andwhich avoids certain drawbacks involved with the bobbin spinning processas hitherto in use. Further objects will be seen from the detailedspecification following hereafter. Reference is made to the accompanyingdrawing in which Figs. 1, 2 and 3 illustrate the process according tothis invention.

Fig. 1 shows twisting in a centrifugal box according to this invention.

Fig. 2 shows a side view of an arrangement for spinning on a platerotating about its axis and simultaneously performing a reciprocatingmovement, and

Fig. 3 shows a front view of the arrangement shown in Fig. 2.

Viscose artificial silks which have been finished by after-treatment onthe spools with liquids sucked or forced through the silk; do not fulfilall the requirements of the textile industry, particularly the weavingindustry; the desulfurization and drying on the spool produces unequalshrinkage in the inner and outer layers of the wound thread, and this isalmost always a cause of lustrous shot-effects in the dyed fabric,whereby the finished goods are depreciated in value or even renderedunsaleable.

Various attempts have been made to overcome this drawback to thepractice of finishing artificial silk on the spool, which otherwise hasthe advantage of shortening the process.

Thus, for example, the spools have been made with cores which areelastic, flexible or otherwise capable of reduction, and various modesof dyeing the threads on the spool have been tried.

None of these experiments, however, has yet been adopted for manufactureon a commercial scale.

By the present invention the quality of artificial silk made fromviscose, spun or spools and, if desired, after-treated thereon, is soconsiderably improved that the silk can be used directly, even forweaving, without producing lustrous shot-effects in the finished fabric.

By the invention the viscose artificial silk washed on spools in theusual manner and, if desired, after-treated thereon, is unwound from thespool before drying and, preferably while simultaneously twisting it, isdeposited in the formof a winding having no interior support.

Alternatively the silk on the spool can be deacidified, and only theinteriorly unsupported winding produced in the twisting processaftertreated and dried.

In this process it is important that the silk should not be dried undertension on the spool, but in the form of the interiorlyunsupportedwinding. By the expression cake having no interior support inthe sense intended herein and in the appended claims is meant anywinding or cake of stable form, not wound on a support, the threadsowing to the manner of winding having suificient cohesion, so that theyare not displaced in relation to one another or tan' gled to anyconsiderable extent. Such cakes or windings are obtained, for example,by collecting the thread on a plate which has both a rotary and areciprocating movement, or in a centrifugal box. As compared with theknown process of working up spool-silk into skeins, the interiorlyunsupported windings have, inter alia, the great advantage that only onetextile operation and only one drying is necessary, and the layers ofthread can yield as desired over the entire length. The new process isintended for operations in connection with spool spinning machines, andconstitutes a new step towards shortening and cheapening the manufactureof viscose silk. The procedure may be varied in many ways. Preferablythe de-acidified or completely after-treated thread is withdrawn fromthe spool from the top and is twisted in a centrifuge. The centrifugalbox may consist of light sheet metal, for example sheet aluminium, andbe mounted on an ordinary twisting machine. Instead of a centrifugal boxthere may be used a slowly rotating plate, which in addition to therotation has a reciprocating movement. It is, however, also possible torotate both the spool from which the silk is withdrawn and the receivingdevice, whereby the thread is doubly twisted.

When stationary spools are used it has been found to be advantageous inthe twisting process to place the spools in liquid containingpreparatory agents or soaping agents, so that in this manner the threadmay be prepared as thoroughly as desired. The thread is then centrifugedin the collecting box and is thus quite uniformly permeated with thepreparatory agents, which is of paramount importance for the subsequentoperations.

The following examples illustrate the invention:

Example 1.--A silk spun on spinning spools, de-acidified, de-sulfurizedand completely aftertreated, is directly subjected, without the usualdrying operation, to the twisting process in which the thread is drawnoff the spool from the top, passed over a galette and twisted into alight centrifugal box, or to be more precise, an internal-windingspindle. The draft, produced by the galette, amounts, for example, to 50m., and the number of revolutions of the twisting spindle is 6000. It ispreferable to use artificial silk spools spun as thick as possible inorder to obtain spun threads of the maximum length. The completelytwisted cake is then dried on rods or pins while avoiding tension, andcan either be improved directly on cross-wound bobbins or cops, or be atonce offered for sale.

If it is desired to provide highly prepared artificial silk, thespinning spool is placed in a vessel with the desired preparatoryliquid, as shown in Fig. 1 of the accompanying drawing.

Example 2.Viscose artificial silk spun on spinning spools is onlyde-acidified and then, in wet state is drawn off from the top andtwisted into a centrifugal box, in a manner similar to that described inExample 1. The cake is then desulfurized in known manner by mounting itin a permeable tube and forcing or sucking liquid through it, and isfinally dried without tension.

Example 3.The completely after-treated, still wet spinning spool isplaced on a twisting spindle and subjected. to a normal twistingprocess. The draft is produced by a galette and the thread is receivedon a reciprocating plate-mechanism (see drawing No. 2).

The invention will now be described with reference to the accompanyingdrawing.

Fig. 1 shows an arrangement for twisting artificial silk wound onbobbins which has been washed and eventually after-treated. From thenon-rotating bobbin a the thread is unwound over-head by means of thegalette c and twisted into the centrifugal box (1. The thread unwoundfrom the bobbin is guided through the thread guide eyelet b. Thecentrifugal box is quickly rotated about its vertical shaft by means ofthe wheel is mounted on said shaft. At the centrifuged liquid flowsaway.

Fig. 2 shows a side view of a twisting device with which the thread isunwound from the bobbin a rotating at a high speed. The thread is drawnoff by means of the galette c, the thread being wound twice around it,so that it dips into a bath 7!. of liquid under the galette. b and i arethread guide eyelets. The bobbin from which the thread is unwound, is bymeans of the wharve g quickly rotated by a driving belt. The twistedthread is collected on a plate which is driven in such a manner that thethread is deposited in the form of wellformed intericrly unsupportedwindings.

Fig. 3 shows a front view of part of a twisting machine with twospindles. The thread is unwound from the bobbin a which is quicklyrotated. The galette 0 effects unwinding of the thread from the bobbin.The plate I on which the thread is collected is driven by a planetarygearing so that a winding with a stable form is produced.

What I claim is:

1. In the manufacture of viscose artificial silk according to the bobbinspinning system wherein a spun thread is wound on a bobbin, deacidified,desulfurized and washed, and thereafter is dried, the improvement whichcomprises drawing the thread, after washing and prior to the dryingthereof, off of the bobbin by passing the same over a draft device,twisting the wet thread and collecting the same in the form of a cakehaving no interior support, and thereafter drying said cake while itsinterior is unsupported.

2. The improved process defined in claim 1, in which the twisted threadis collected in the form of a cake having no interior support byreceiving the thread on a plate which in addition to rotating on itsaxis also performs a reciprocating movement.

3. The improved process defined in claim 1, in which the twisted threadis collected in the form of a cake having no interior support byreceiving the thread in a centrifugal box.

4. The improved process defined in claim 1, in which the thread is drawnoff of the bobbin through a bath of treating liquid.

PAUL ESSELMANN.

